Tsukasa Kiriki appears as an ordinary, timid high school student in Hiroshima, masking significant underlying potential. Hailing from a wealthy background as a "rich bonbon," he enters the delinquent world through impure motivations rather than inherent criminality, drawn in after encountering Gokuraku Cho members Yoji, Hisao, and Eiji. A pivotal confrontation sees Tsukasa defeat the gang's existing leader, unexpectedly elevating him to become Gokuraku Cho's eighth-generation leader despite his initial reluctance and lack of imposing physicality. His defining trait emerges when provoked: extraordinary strength and ferocity, especially triggered by protecting others or confronting injustice. This duality—passive composure versus explosive capability—anchors his leadership identity.

Navigating complex gang rivalries within Hiroshima, particularly against more powerful groups like Hidenori Danno's "Beast" and "Nights," forces Tsukasa's maturation. He evolves from an inexperienced outsider into a more strategic and resilient figure, honing the balance between aggression and responsibility while pushing Gokuraku Cho toward recognition as one of Hiroshima's top three gangs. Relationships with allies, including romantic ties to Yoshimoto Kumi, further shape his growth, reinforcing his protective instincts and loyalty.